9 Replies

This is a normal change, we migrated to office365 recently as well. This is because of the way that office365 integrates with Exchange.

It should only prompt once for this change, and (more than likely) ask for the user credentials again. Open Credential manager, delete any exchange cached credentials, relaunch Outlook. Enter the user credentials as "user@yourdomain.com" and the password.

If it continually prompts for your credentials, you need to update the machine (use the office365 setup tool, this can be found when you login as the user to your office 365 portal) It checks for any updates that are missing and installs them.

How is your exchange environment hosted? Are you using OAUTH, NTLM or Basic authentication? Has your method changed since your migration? I have a feeling it likely has.

If you previously used Basic Authentication, the default (i believe gets changed to OAUTH). I'd still check the Credentials Manager (Windows 7 you can start search it) and remove any cached credentials. See what happens from there.